The present disclosure relates to an image processing apparatus, an image processing method, and a program and, in particular, to an image processing apparatus, an image processing method, and a program capable of restoring detail clarity of any area of an image.
In general, “information” has bias (universality) of energy (entropy). This bias is recognized as information (valuable information).
For example, an image obtained by shooting a certain landscape is recognized as the image of landscape by a human being because the image (the pixel values of pixels constituting the image) has a bias of energy corresponding to that landscape. An image having no bias of energy is only noise or the like and is useless as information.
Therefore, even when the original bias of energy of valuable information is “destroyed” by manipulating the information in a certain way, the original information can be restored from the information subjected to the manipulation by restoring the destroyed bias of energy to the original bias of energy. That is, data obtained by manipulating the information can be restored to the original valuable information by using the original bias of energy of that information.
For example, part of an image obtained by shooting a landscape can be created using fractals (self-similarity) of the image. In an image including the images of, for example, the sea and wood, a similarity between a variation pattern of the pixel values of the entire image of the sea (e.g., the shape of the edge) and a variation pattern of the pixel values of part of the image of the sea is high. In contrast, a similarity between the variation pattern of the pixel values of the sea and a variation pattern of the pixel values of the image of the wood that is located away from the sea is low. That is, such a bias of the similarity appears.
Let part of the image of the sea be exchanged by part of the image of the wood.
Then, an image having a destroyed bias of the similarity can be obtained. However, by using the following bias of a similarity, the destroyed bias of similarity can be restored. That is, the bias of similarity indicates that the similarity between the variation patterns of pixel values of close parts is high and that as the distance between the parts increases, a similarity between variation patterns of pixel values of the parts becomes lower.
That is, according to the original bias of the similarity appearing in landscape images, it is clearly unnatural that part of an image of the sea is part of an image of a wood having a low similarity to the sea and, in addition, part of the image of the wood is part of the image of the sea. That is, the similarity in variation pattern between the image of the sea and part of the image of the wood present in the image of the sea is significantly lower than the similarity between part of the image of the sea and the other part of the image of the sea. In addition, the similarity in variation pattern between the image of the wood and part of the image of the sea present in the image of the wood is significantly lower than the similarity between part of the image of the wood and the other part of the image of the wood. In contrast, each of the similarity between the part of the image of wood present in the image of the sea and the image of the wood and the similarity between the part of the image of the sea present in the image of the wood and the image of the sea is high.
Therefore, according to the original bias of the similarity appearing in landscape images, it is desirable that the part of the image of wood present in the image of the sea be exchanged with the part of the image of the sea present in the image of the wood. By performing such exchange, the bias of the similarity in the image can be restored. In this manner, an original image can be restored.
In addition, by using such self-similarity in an image, image processing to improve the image quality can be performed. In such processing to improve the image quality using a self-similarity, a technique for improving the continuity of an image in a boundary portion has been developed (refer to, for example, Japanese Unexamined Patent Application Publication No. 11-331595).